.paper {
    position: relative;
    background-color: var(--paper);
    background-image:
        linear-gradient(
            to right,
            color-mix(
                    in oklab,
                    var(--grid-line) calc(var(--grid-alpha) * 100%),
                    transparent
                )
                1px,
            transparent 1px
        ),
        linear-gradient(
            to bottom,
            color-mix(
                    in oklab,
                    var(--grid-line) calc(var(--grid-alpha) * 100%),
                    transparent
                )
                1px,
            transparent 1px
        ),
        linear-gradient(
            to right,
            color-mix(
                    in oklab,
                    var(--grid-line-2) calc(var(--grid-alpha) * 100%),
                    transparent
                )
                1px,
            transparent 1px
        ),
        linear-gradient(
            to bottom,
            color-mix(
                    in oklab,
                    var(--grid-line-2) calc(var(--grid-alpha) * 100%),
                    transparent
                )
                1px,
            transparent 1px
        );
    background-size:
        calc(var(--grid-size) * 5) calc(var(--grid-size) * 5),
        calc(var(--grid-size) * 5) calc(var(--grid-size) * 5),
        var(--grid-size) var(--grid-size),
        var(--grid-size) var(--grid-size);
    background-position: -1px -1px;
}

.paper-fade::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(
        ellipse 80% 60% at 50% 0%,
        transparent 40%,
        var(--paper) 100%
    );
    pointer-events: none;
}

/* =========================================================
   Nav
   ========================================================= */
.nav {
    position: sticky;
    top: 0;
    z-index: 40;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 32px;
    background: color-mix(in oklab, var(--paper) 85%, transparent);
    backdrop-filter: saturate(140%) blur(8px);
    -webkit-backdrop-filter: saturate(140%) blur(8px);
    border-bottom: 1px solid var(--rule);
}

.nav .logo {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 34px;
    border: 1.5px solid var(--accent);
    border-radius: 8px;
    background: var(--paper);
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--accent);
    font-size: 14px;
    letter-spacing: 0.02em;
}

.nav-brand {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 34px;
    border: 1.5px solid var(--accent);
    border-radius: 8px;
    background: var(--paper);
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--accent);
    font-size: 14px;
    letter-spacing: 0.02em;
    text-decoration: none;
}

.nav-name {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--ink-4);
    letter-spacing: 0.04em;
}

.nav nav {
    display: flex;
    gap: 28px;
    font-family: var(--font-sans);
    font-size: 14px;
}

.nav nav a {
    color: var(--ink-2);
    text-decoration: none;
    padding: 6px 4px;
    position: relative;
    transition: color 0.15s;
}

.nav nav a:hover {
    color: var(--ink);
}

.nav nav a.active {
    color: var(--accent);
}

.nav nav a.active::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: -15px;
    height: 2px;
    background: var(--accent);
}

.nav-links {
    display: flex;
    gap: 16px;
    align-items: center;
}

.nav .tools {
    display: flex;
    align-items: center;
    gap: 8px;
}

.icon-btn {
    width: 34px;
    height: 34px;
    border-radius: 8px;
    border: 1px solid var(--rule);
    background: var(--paper);
    color: var(--ink-2);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition:
        background 0.15s,
        color 0.15s,
        border-color 0.15s;
}

.icon-btn:hover {
    background: var(--paper-2);
    color: var(--ink);
    border-color: var(--ink-4);
}

.lang-pill {
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.05em;
    padding: 6px 10px;
    border: 1px solid var(--rule);
    border-radius: 999px;
    background: var(--paper);
    color: var(--ink-3);
    cursor: pointer;
}

.lang-pill b {
    color: var(--ink);
    font-weight: 600;
}

/* =========================================================
   Type scale — academic
   ========================================================= */
.eyebrow {
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ink-3);
}

.h-display {
    font-family: var(--font-serif);
    font-weight: 400;
    font-size: clamp(36px, 4.2vw, 58px);
    line-height: 1.05;
    letter-spacing: -0.02em;
    color: var(--ink);
}

.h-display em {
    font-style: italic;
    color: var(--accent);
}

.h-title {
    font-family: var(--font-serif);
    font-weight: 500;
    font-size: 24px;
    line-height: 1.25;
    letter-spacing: -0.01em;
}

.h-section {
    font-family: var(--font-sans);
    font-weight: 500;
    font-size: 13px;
    letter-spacing: 0.02em;
    color: var(--ink-3);
    text-transform: uppercase;
    letter-spacing: 0.14em;
}

.body {
    color: var(--ink-2);
    font-size: 16px;
    line-height: 1.7;
}

.mono-label {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--ink-3);
    letter-spacing: 0.02em;
}

/* link */
.inline-link {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid color-mix(in oklab, var(--accent) 40%, transparent);
    transition: border-color 0.15s;
}

.inline-link:hover {
    border-bottom-color: var(--accent);
}

/* Tag */
.tag {
    display: inline-flex;
    align-items: center;
    font-family: var(--font-mono);
    font-size: 11px;
    padding: 3px 8px;
    border-radius: 4px;
    background: var(--paper-2);
    color: var(--ink-3);
    border: 1px solid var(--rule);
}

.tag.blue {
    color: var(--accent);
    background: var(--accent-soft);
    border-color: color-mix(in oklab, var(--accent) 30%, transparent);
}

/* Tiny scroll niceties */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-thumb {
    background: var(--rule);
    border-radius: 8px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--ink-4);
}

/* Focus ring */
:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

/* Container */
.container {
    margin: 0 auto;
}

html {
    width: 100vw;
    height: 100vh;
    overflow: hidden;
}

/* Grid layout */
.grid {
    min-height: 100vh;
    overflow: hidden;
}

/* Content area */
.content {
    padding: 0;
    overflow: hidden;
}

.nav-progress-bar {
    position: fixed;
    background: var(--accent);
    top: 4rem;
    left: 0;
    height: 2px;
    width: 0%;
    border-radius: 2px;
}